title: Age-specific and sex-specific morbidity and mortality from avian influenza A(H7N9).
abstract: We used data on age and sex for 136 laboratory confirmed human A(H7N9) cases reported as of 11 August 2013 to compare age-specific and sex-specific patterns of morbidity and mortality from the avian influenza A(H7N9) virus with those of the avian influenza A(H5N1) virus. Human A(H7N9) cases exhibit high degrees of age and sex bias: mortality is heavily biased toward males >50 years, no deaths have been reported among individuals <25 years old, and relatively few cases documented among children or adolescents. The proportion of fatal cases (PFC) for human A(H7N9) cases as of 11 August 2013 was 32%, compared to a cumulative PFC for A(H5N1) of 83% in Indonesia and 36% in Egypt. Approximately 75% of cases of all A(H7N9) cases occurred among individuals >45 years old. Morbidity and mortality from A(H7N9) are lowest among individuals between 10 and 29 years, the age group which exhibits the highest cumulative morbidity and case fatality rates from A(H5N1). Although individuals <20 years old comprise nearly 50% of all human A(H5N1) cases, only 7% of all reported A(H7N9) cases and no deaths have been reported among individuals in this age group. Only 4% of A(H7N9) cases occurred among children<5 years old, and only one case from the 10 to 20 year age group. Age- and sex-related differences in morbidity and mortality from emerging zoonotic diseases can provide insights into ecological, economic, and cultural factors that may contribute to the emergence and proliferation of novel zoonotic diseases in human populations.
authors.affiliation: Science Applications International Corporation, 12530 Parklawn Drive, Suite 350, Rockville, MD 20852, USA; Institute of Arctic Biology, University of Alaska Fairbanks, USA; Department of Earth Sciences, University of Alaska Museum, USA. Electronic address: Joseph.P.Dudley@saic.com.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Dudley
authors.forename: Ian M
authors.initials: IM
authors.lastname: Mackay
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053124:Influenza A Virus, H5N1 Subtype / Q000302:isolation & purification; D064766:Influenza A Virus, H7N9 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000453:epidemiology / Q000401:mortality* / Q000473:pathology* / Q000821:virology; D008297:Male; D008875:Middle Aged; D009026:Mortality; D012720:Severity of Illness Index; D012737:Sex Factors; D016019:Survival Analysis; D055815:Young Adult
keywords: A(H5N1); A(H7N9); Age-specific; Avian influenza; Emerging diseases; Zoonoses